The present invention relates to a bone clamp used in surgical procedures for repair of bone fractures requiring fixation for the proper mending thereof, and more particularly, to a bone clamp for use in compression of transverse fractures for subsequent fixation by suitable means while retained in abutted contact following open reduction of the fracture.
A variety of bone clamps are commercially available for reducing bone fractures, i.e. the process of urging fractured portions of a bone into proper alignment with one another. Generally falling into two categories, bone clamps include parallel and perpendicular types, designated in accordance with the orientation of the axis of the device with respect to the axis of the fracture. A parallel bone clamp approaches the axis of the fracture parallel with its own axis. A perpendicular bone clamp approaches the axis of the fracture with its own axis perpendicular to the axis of the fracture.
Included among the more commonly used parallel bone clamps are the Verbrugge, the Lange, the Kern, the Ulrich, the Lambotte, the Seidel, and the Lanenbeck. Each of these clamping devices utilizes a ratchet mechanism to apply and maintain pressure on the severed portions of the bone being urged into mutual contact alignment.
In addition to the aforementioned clamps specifically designed for reduction procedures, surgeons have for many years routinely relied upon the common towel clip to reduce fractures and effect repair of bone fractures, in particular where small bones were involved. Deriving its name from its originally designed purpose of holding towels together in a sterile field, the towel clip was never expressly intended for use in bone fracture surgery. When applied to use as a bone repair device, the towel clip falls into the category of the aforementioned parallel type bone clamps, its shape resembling a pair of miniature ice tongs having a pair of sharp, opposing points which may be brought together by scissor action, and which serve to securely grip the bone from opposed sides thereof. A ratchet mechanism assists in applying pressure on a fractured bone interposed between the points, and maintains pressure on the bone without requiring continued manipulation thereof by the user. The towel clip has found application as a device used in small bone reductions because it occupies less space than most parallel bone clamps. In addition, its rugged design permits the application of relatively large forces required to reduce bones and the two sharp points reliably grasp the opposed bone surfaces without slipping. Its design, however, is not adapted to use in circumstances in which a transverse fracture separates the bone segments requiring reduction and securement for subsequent fixation, since gripping by the towel clip relies upon single points positioned in direct opposition from one another across the longitudinal direction of the involved bone.
A bone clamp is proposed in U.S. Pat. No. 5,578,032 entitled "Bone Clamp", and issued to Lalonde on Nov. 26, 1996 having structure falling into the aforementioned perpendicular bone clamp category, and in accordance with which the instrument is inserted into the wound crosswise to the fractured bone. Its special configuration is uniquely adapted, in particular, for use in repairing small fractures. The disclosed bone clamp includes a pair of clamps extending perpendicular to a ratcheted scissor portion. The clamps, each having one or more sharp points at an end thereof, may be urged together by operation of the scissor portion, thereby contacting opposed sides of a bone positioned therebetween. Since the aforementioned clamp provides only a single pair of opposed points, or plural points spaced apart on each clamp only a minimal distance from one another, the design is exclusively suited for repair of oblique fractures, wherein the fracture line runs crosswise between a compression axis of the opposed clamps brought into engagement with the bone segments, and does not offer a satisfactory solution to the problem of open reduction of transverse fractures.
Also disclosed in the above Lalonde patent is an embodiment directed to a device comprised of two bone clamps mounted on a slide bar to permit approximation of the bone clamps, each gripping a separated bone segment. Continued approximation of the clamps one to the other results in reduction of the bone segments and permits subsequent fixation by accepted methods.
In addition to the aforementioned non-dynamic compression devices in which the reduced bones segments are maintained in aligned contact without application of any additionally applied axially compressive forces, a device is described in the prior art which permits dynamic compression of the fracture for better engagement of abutted ends of the adjacent bone segments, thought to result in improved healing and recovery. The known device, a type of bone plate which acts as an internal splint while the bone heals, is affixed to the bone in a position spanning the fracture site. The bone plate is generally contoured to conform to the shape of the bone, and is fixed in place by the use of screws which self-tap into the bone. To provide dynamic compression, the specialized bone plate, the structural and operational aspects of which are described for example in "Manual of Small Animal Fracture Repair and Management", pages 80-81, and which is incorporated herein by reference, includes holes within which screws, received therethrough and into respective aligned bone segments, can slide axially. The holes are provided with eccentrically configured shoulders which impart sliding motion to the screws as they are tightened, which in turn results in axial movement also of the bones into compressive abutted engagement. Although quite effective in achieving dynamic compression, use of such plates does not allow a surgeon the option of using other fixation methods, and further requires separate use of a bone clamp to maintain alignment while applying such plate.
A clamp design would therefore be desirable by means of which a reduced transverse fracture could be immobilized to permit fixation by a desired method prior to removal of the clamp, and which could advantageously provide dynamic compression attendant a clamping operation whereby subsequent fixation which would not necessarily be limited to use of a bone plate.
Accordingly, it is an object of the invention to provide a bone clamp which overcomes the drawbacks of the prior art.
It is a further object of the invention to provide a bone clamp which may be inserted into a surgical incision for maintaining bone segments separated by a transverse fracture in a reduced state to permit subsequent fixation thereof.
It is a still further object of the invention to provide such bone clamp in a form utilizing a ratchet mechanism for simple and efficient operation, and which thereby permits hands-free maintenance of the clamped positioning of the fracture during subsequent mending thereof.
It is yet a further object of the invention to provide a bone clamp which may be used to provide dynamic compression of a fractured bone following reduction of the bone segments and subsequently maintaining axially compressive alignment for fixation by a desired method.
It is yet a further object of the invention to provide a bone clamp of the above type which is economical, yet rugged enough to withstand the forces of bone reduction.